Field of the Invention
This invention relates generally to cooling systems for building structures, and more particularly, relates to an improved evaporative air cooling system.
Description of the Related Art
Fans, air conditioners, and various other systems have been developed for cooling residential and commercial building structures. Most fan systems are designed to create airflow inside a building. Since fans are incapable of lowering the actual temperature of the air drawn into the building, their cooling effect is limited by the ambient air temperature. While air conditioners are capable of lowering the temperature of the ambient air, they are not energy efficient or environmentally friendly.
Evaporative coolers are often utilized as an energy saving alternative to cool the living space of a building structure, particularly in dry climate regions. An evaporative cooler typically includes a large fan and water-wetted pads that are all enclosed inside a metal or plastic housing. Fresh outside air is cooled as it is drawn through vents on the housing walls to the wet pads located therein. The cooled air is then blown into the building structure. While conventional evaporative coolers are energy-efficient and effective, the systems are typically enclosed in large and bulky structures that can be obtrusive and unsightly when placed adjacent to the exterior of the building structure. Additionally, a large motorized blower is usually mounted inside the enclosure to push the cooled air into building structure. The blower can force excessively moist and humid air into the building structure, leaving it damp and odorous. Moreover, the high noise level generated by the motor, which is usually positioned immediately adjacent the exterior wall of the dwelling area, can also be bothersome, thus making using conventional evaporative coolers less desirable.
U.S. Pat. No. 4,951,480 discloses an evaporative cooling system having an evaporative cooling unit located within an exterior wall of a house and one or more remote exhaust fans mounted in the attic. The idea is to utilize the remotely located exhaust fans to pull air through the evaporative cooling unit into a space to be cooled and also to exhaust the warm air from the space. However, the design of this system is inherently limiting and incapable of effectively cooling a house, especially a house with large square footage. One of the drawbacks is that the exhaust fans are typically low power fans and they are mounted openly in an attic located far away from the evaporative cooling unit. These exhaust fans cannot effectively pull air from outside through the evaporative cooling unit and expel warm air from the attic, especially when there is a great distance between the fans and the cooling unit. At best, the exhaust fans facilitate ventilation of the attic by helping to drive out some of the warm air. The inherent limitations of this design seem to suggest that in order for the system to work, it must rely in large part on convection of warm air to create upward air movement, which in turn draws outside air through the cooling unit. When air is drawn through the cooling unit into the house in such a passive manner, the cooling effectiveness is likely to be very limited. Additionally, the attic area is likely to be filled with warm air given the inherent inability of the exhaust fans to push all of the warm air out of the attic area. Warm air in the attic in turn is likely to cause other areas of the house to be uncomfortably warm.
In view of the foregoing, there remains a need for an unobtrusive, energy-efficient, environmentally friendly, and effective system and method for cooling a building structure. The preferred embodiments of the present invention are designed to address at least one of the above-described shortcomings of conventional cooling systems.